Metal stretch bending apparatus



July 12, 1960 R. M. AHONEN METAL STRETCH BENDING APPARATUS 4 Sheets-Sheet 1 Filed May 8, 1959 INVENTOR. RAYMOND M. AHONEN ATTORNEY July 12, 1960 R. M. AHONEN METAL STRETCH BENDING APPARATUS 4 Sheets-Sheet 2 Filed May 8, 1959 INVENTOR. RAYMOND M. AHONEN ATTORNEY July 12, 1960 R. M. AHONEN METAL. STRETCH BENDING APPARATUS 4 Sheets-Sheet 3 Filed May 8, 1959 INVENTOR. RAYMOND M. AHONEN Kw, om mm .H--- m .qiifig mwl\ II 1 81 t I a m m m m m wr I I a w\\\\ J J m vm mm Ni w ATTORNEY July 12, 1960 Filed May 8, 1959 R. M. AHONEN 2,944,582

METAL STRETCH BENDING APPARATUS 4 Sheets-Sheet 4 FIG. 6

FIG. 8

IN VEN TOR. RAYMOND M. AHON EN BY mm ATTORNEY 2,944,582 r a METAL STRETCH sunnmo APPARATUS Raymond M. Ahonen, Southfield Township, Oakland County, Mich., assignor to Century Die & Manufacturing Company, Hazel Park, Mich., a copartnership of Michigan Filed May 8, 1959, Ser. No. 811,885 7 v Claims. (Cl. 153-40) This invention relates to metal stretch bending apparatus and more particularly to apparatus for stretch bending a flat or semi-formed band or strip of metal into a curved molding about die forms arranged on complementary symmetrical mechanisms.

This application is a continuation in part of my earlier patent application Serial No. 630,164 filed December 24, 1956, issued as US. Patent No. 2,887,143 on May 19, 1959.

In general, the apparatus of this invention involves a split forming die of curved configuration to stretch bend a band or strip of metal into a curved molding piece, a pair of complementary die segments arranged for horizontal and vertical rotation, clamps associatedly" conjoined with the die segments to hold the ends of the work piece upon the outer ends of the split die form, laterally slidn t d *P i fjOf ing guided cam controlled plates upon which the die seg- I ments pivot for horizontal swinging movement, and 'vertical cams'upon which the die segments ride during- ,their period of vertical swinging. The die segments are pivotally mounted on horizontally rotatable plates or elements which are provided with cams adapted to bear upon base mounted cam followers, pivotally mounted in fixed positions upon a machine base intermediate the slides supporting the die segments. Power drive means is artic'ulatedly connected to, the platemembers to rotate them and their cams against the cam followers, causing the slide supports to carry the horizontally rotating and vertically'pivoting die segments into .alignment at their inner ends as the work piece is, stretched and bent about and upon the die form, ;By providing a vertical slide supported cam for one or bothof the. rotating die segments, the work piece, clamped at the outer ends of the die form sections, is caused to bend in a vertical path aswell as in a horizontal plane, providing a com- .pound curve in the molding. Such moldings are much used in automobiles about Windshields and other window provide vertical cams for the horizontally rotating die segments to cause them to pivot vertically.-

These, and other objects of the inventionand, features of construction will become more apparent from the description given below,-in which. the. terms employed aroused for purposes of descriptionand; not-of-limitation.

Reference is here made to therdrawings annexed hereto "and madeian integral part hereof,,i1 1 which Fig. 1 is a top plan 'view of the :appalfatusof this invention, showing the complementary die segments in closed aligned position.

wa July, 12,, 1960 I Fig.1 z'is a top plan viev voof the machine of Fig. 1,

showing the die segments 'inopen position, the metal work piece being shown. in broken lines, with the end clamps. in open or retractedposition. I i

Fig. 3' is a fragmentary enlarged front elevational view of the left hand side ofrthe machine shown in Fig. 1, with parts broken away to show a portion of the apparatus below the top plate. V

Fig. 4 is a horizontal sectional view, partially in plan, of the clamping mechanism associatedly conjoined with one-of the die segments, the clamp being-arranged in open position.

'Fig. 5 is a View similar to Fig. 4 showing the clamping mechanism in closed position. 7

Fig. 6 is a fragmentary vertical sectional view taken substantially on the line 6-6 of Fig. 5.

Fig. 7 is a diagrammatic outline of the hydraulic system for the machine shown in Figs. 1-3 inclusive.

Fig. 8' is a perspective view of a finished molding produced by a machine of the type here disclosed, having a compound curvature developed by virtue of both horizontal rotation and vertical pivoting of the die segments. The metal stretch bending machine .or apparatus of this invention is generally symmetrical in character and arrangement and "will be described as a double bend machine, i.e. a machine in which complementary die segments are actuated to form a metal strip or band into a finished molding of compound curvature.

As shown in theseveral views of the drawings, and particularly in Figs. -13 inclusive, the metal stretch bending machine 10 is arranged with a machine base 12 having a top plate base 14' to provide a suitable support for the stretch bending mechanism. On the top plate base 14 are two pairs of parallel slide guides or gibs 16,1arranged in alignment and .opposed to'eachother, in which the segmented stretch. bending mechanism is Slidingly mounted. This mechanism comprises a' pair of complementary die segments 18 and 20, right and left, respectively, slide plates or die support mounts 22 and 24 0a which the die segments 18 and 20 are respectively horizontallypivotallyimounted, clamping .rnec-hanismslpfi and 128 .attheouter endsv of the die segments 18 and 20 respectiv ly, cams 30, and 32, right and left respectively, fixedly mounted on the die segment support plates 34' and 3.6, right; and leftrespective'ly, and top plate base mounted, cam rollers or followers 38 and 40, right and left respectively. A hydraulic, drive system, designated generally by the reference numeral 42, Fig. 7,

operates the mechanisms of themachine 10.

' The machine base 12 is arranged with vertical Walls or sides conjoinedlto the top plate base 14-to form a substantially box-typesupport, A hydraulic cylinder 44' is mounted upon the plate 14 rearwardly of the mech- .anism above described, andis of usual construction including an inlet conduit 46 at the rear end of the cylinder ,for hydraulic fluid -to drive a' piston 48 forwardly,

. Thefunction of control valve 58 is to limit the return m v m ntof he p s n rod, d -t0 n rti rgy, which might cause the clamping mechanisms 26 and 28 to swing I ontwardlytootar from the die segments 18 and 20, a d to bring :the clamping'mechanisms and die segments into a POSitive prede r in starti g .relatlon hip- T e control v l e5 e 99mn1i ee th inact on y c osin 2,944,582 in e oil? the hydraulic fluid in the system against entrance into the cylinder 44. V

The elongated projecting piston rod 52 is arranged witha terminal cross member 62, which moves slidingly on a supporting guide member 63 mounted on top plate 14 and projecting slightly forward of the machine base 12. Pivotally connected by yokes 64 to cross member 62 at either end thereof are a pair of adjustable links 65 having yokes 66 aflixed at their opposite ends.

In view of the symmetry of the stretch bending machine or apparatus 16, it is deemed sufficient to describe in detail one of the two complementary portions of the mechanism, it being understood that the second portion is substantially identical in parts and conjoined arrangement except that the second portion is disposed in inverse relationship. The portion to be described in greater detail is located to the left of the piston rod 52, as shown particularly in Fig. 3.

As shown in Figs. 1-3 inclusive, the slide plate or die support mount 24 is slidingly mounted in guides or gibs 16, 16. Pivotally supported in a vertical bearing 68 on slide plate 24, is a hub 70 having a bearing flange 72 resting on the plate 24 and a sleeve 74 rotatable in bearing 6%. The top plate 14 is cut out at 76 to allow for free oscillating lateral movement of the bearing 68 therethrough, permitting the bearing to project below the top plate, where a rod 80 is slidingly mounted transversely on the lower end of the bearing. At the lower The die segment support plate 36 is fixedly conjoined to the hub 70 and provides the mount for attachment below, in the same plane, or above, of the cam 32, and

for attachment of the lever plate member 94 the innerend of which is pivotally linked at 96 to the yoke 66. Cam 32 is arranged to operatively bear on cam roller or follower which is pivotally and rotatably mounted on pivot bearings 98 affixed to the top plate 14.

surmounted on lever plate 94 is the die segment 20 embodying the die form of the configuration into which the metal strip is to be stretch bent, the outer end of the die segment being link connected to the band clamping mechanism 28. Aflixed to the rearward edge of the die segment support plates 34- and 36 are the clamp limiting guides 106 and 102, respectively, which serve to limit the rotative movement of the clamp bearings at the stops 164 and 106, as shown in Figs. 1 and 2.

The clamping mechanisms 26 and 28 each comprise a hydraulic piston type cylinder 112 having a piston rod 114 projecting therefrom at the end of which is affixed the joint 116. Pivotally mounted at 118 on the end of the joint 116 is a bell crank 120 having a central pivot 122 and an end pivot 124 mounted in clamp housing 126. Linked at one end to pivot 122 is a lever 128 having a pivot 130 slidingly mounted in upper and lower slots 132 arranged in the upper and lower walls 134 of housing 126. At the forward end of the housing 126 is a clamping bar or anvil 136, designed to close over the end of a metal band work piece laid upon the ends of the die segments 18 and 20. A linking member 138 is pivotally afiixed at one end to the lever 128 by the pivot 13th and is positively and fixedly secured to the outer end of the die segments 18 and 20 as the case may be. The cylinder 112 is pivotally mounted at pin 146 by yoke148 to a support block 150 which is fixedly mounted on the lever plate 94. A toggle break member 152 is em bodied in a clamp housing 126 at the outer side thereof, comprising a tubular sleeve 154 closed at its outer end and threaded exteriorly to screw into a threaded opening .156 in the housing 126, and a headed pin 158 slidably sleeve 154-.

As shown in Figs. 1-3 and 8, the metal band 2%, initially a substantially straight semi-formed strip having, as an example, only the cr oss-sectional contour shown in Fig. 6, is laid upon the ends of the die segments 18 and 2t), ready for closing of the clamping bars 136. A transverse embossment is provided on the end portion of the die segment in direct contact with the metal band 264). 'A complementary recess 142 is provided in the clamping bar or anvil 136.

The die'segments 18 and 20 are arranged for vertical pivoting by means of a bearing block 162 fixedly mounted on each die segment, a bearing block 164 fixedly mounted on each die segment support plate 34- and 36, and a pivot pin 166 rotatably positioned in both blocks. Fixedly mounted on each slide plate 22 and 24 is a vertical cam 168 having the cam surface contour required for a particular application or part. A cam follower 170' is pivotally and rotatably mounted on each die segment 18 and 26 in a position to bear upon the vertical cam 168, so that as each die segment is rotatably horizontally pivoted on its bearing 68 the die segment will pivot in a vertical plane on the pivot pin 166 as the cam follower 17h rides upon the vertical cam 16%. Although the vertical cams are shown positioned. at the outer ends of the die segments 18 and 26, it will be understood that the cams 168 may be placed at other positions within the sweep of the die segments, the horizontal pivot pin 166 also being arranged in a different position, if necessary, to accommodate the requirements of a particular application or part.

The hydraulic system 42, shown diagrammatically in Fig. 7, comprisesan electric motor 262 driving a pump 204 which feeds hydraulic fluid, preferably oil, through a pressure regulator valve 266, a check valve 268 to a four-way valve 216 whose component units are designed to pass fluid to the control valve 58 mounted on top of cylinder 44, and through this valve to the cylinder 44. Valve 210 also passes hydraulic fluid to the clamping cylinders 112 which operate the clamping mechanisms 126 and 123. A fluid supply tank 214 is provided in the base of the machine '10 for use bythe pump 2M and for discharge of exhaust fluid from the valve 216.

The metal stretch bending machine 10 is operated by control switch mechanisms not shown. These switches may be of several types, the electrical push button being preferred. In each instance, an operation of the machine is accomplished by actuating a control device which causes a part or parts of the apparatus to function in accordance with its structure and organizational arrangement. To start the machine 10 the motor 202 is energized operating the hydraulic pump 204. In the open machine position shown in Fig. 3 a metal band work piece is laid upon the ends of the die segments 18 and 20 over the embossments 140. The clamping mechanisms 26 and 28 are closed over the ends of the work piece by operation of the control valve 210 which passes fluid to the clamping cylinders 112. When the clamps close over the ends of the band 200, the embossments 140 and, the clamp bar recesses 142 grip the metal band firmlyand positively prior to the stretch bending operation. v v 7 Valve 210 passes fluid to the control valve 58 which in turn passes it to the master cylinder 44, through inlet conduit 46, forcing piston rod 5 2 forward. As rod 52 moves forwardly, the die lever plates 94 are rotated by linkage 66, 65, 64 and. 62 about their pivot bearings 68 until the inner endsof the die segments 18 and'20 come forward to a contiguous closed alignment, as, shown in Fig. 1. 7 As the die lever plates 94 rotateon their pivots 68, the band 200 is stretched between the endsio f the die segments upon and by the complementary die forms on ,and f242freely slide laterally in; the "gibs 16 to' allow for g Y the stretch forming action of the die segments-as; the cams. 305 and 32; bear against the table-fixed cam followers 38 and. respectively. The metal band 200 holds the tWQ dieunits against their. respective cam followers and toward eachoth'er. 1 i 1 f When the band has been stretchformed to the die, configuration, the control valve 210:is. actuated to pass hydraulic fluid to the clamping cylinders 1'12for reversal of the pistons and consequent opening of the clamping mechanisms '26 and'28. Thefinished stretchformed band 200, Fig. 8, is then removed from the die segmentsls and 20. Y

To return the die units to. their initial starting positions, the control valve 210 is actuated to, pass hydraulic fluid to the, master cylinder 44 through the forward: inlet conduit 50, reversing the movement ofth'e pistonrod 52,

retracting it into the, cylinder and swinging the inner end of the die segments rearwardly toward the initial starting position shown invFig. 2. Y

. To avoid inertial uncontrolled movement past the desired starting point, the block member-56,, fixedly mounted on the piston rod 52, makes engaging; contact with the valve rod 60 to open valve 58 and release fluid to the master cylinder 44 whereby the piston therein comes; to a positive-stop. In this Way the hack sweep of the die segments does not override the initial starting position of th mach ne;

' The die segments, 18 and 20. are easily replaceable for theproduction of new and difierent metal band sizes and shapes'without otherwise modifying the apparatus. In some instances, the die segments can be made with removable, replaceable and interchangeable die forms, if such modifications are desirable and/ or economically feasible. Such features are of importance .from the standpoint of machine adaptability and range:

' tical swinging onthe pivot pins 166, .the diesegments :may alternatively be, arranged, to pivot in a plane other than horizontal, as the particular application should require. as e t1h .n v t12 n. .56..v

I w ll be. understood tram t foregoing d sc p o ha r he fl c i e op r io o .thei v pp ra u h r disclosed is based upon and is dependent upon thegcooperative relationship of the die form on the die segments, the die segments and the cams which actuate the lateral sliding movement of the die supports and actuate the vertical swinging of the die segments.

Although the preferred means for driving the apparatuses here disclosed is an oil hydraulic system, it will be understood that other fluids, such as air or other gas, water, etc. may also be employed. Further, the drive means may be mechanical in nature, including gearing, levers, etc. switches and electric brakes on themotor drive can be arranged without difiiculty to meet the needs of the described herein.

This plane in any event will be normal to the and 17. 0, can be: arranged Lin. any othersuitablerela; tionship and: at ,any other suitable anglegas the particular io w ppli ati n may-requir 7 E "The m tal str p orband used withthe appar tuseshe shown and described is; preferablyv longitudinallystraight. In cross-section it may be contoured or-straight dependn ponithe. quireme fth pp i ation; In certain instances, a-straight flat; metal strip, of rectangular-crosssection; maybe stretched and bent into. a curved; form having; a contoured cross-section, dependingupon the cross-sectional nature of the, die forms andthe elements of longi-tudinalcurvaturein the die forms. The .invem tion is not to be considered as solely limitedtoa metal strip having a contoured cross-section.

The" principal advantages of the constructiondiselosed reside in the simplicity of the apparatus, the positive, con; trol of each stage of its operation," the broad scop in stretch forming of intricate,-complex forms as well as -more simple metal forms, and the facile replacement features when die sizes 'and' shapesare changed to produce new product sizes and forms.

Having described the invention in its simplest terms,

it is to be clearly understood that the features of construction may be-changed and varied in greater or lesser degree, without departing from the essence of the inven i n.

I claim:

a 1. In apparatus for' stretch bending met-alstrips. or hands, a top plate base support, a pair of complementary; cam controlled, laterally movable, aligned die support mounts slidingly arranged on said base support, guide means foreach of said sliding die support mounts, each of said mounts having a die segment with metal strip die form thereon; a plate member horizontally rotatably mounted on each ofsaidsliding mounts, each of said die segments being pivotally mounted for vertical swinging on. eachof said plate-members, clamp means conjoined to the outer endof each die segment to releasably grip. andholdi said 'rnetal j strip on. said die forms adjacent the outer ends If mechanical drive means are used suitable limit Although the vertical pivot means 162, 164 and 166, p

- of the drawings, this means can also be arranged so that it is parallel to the diesegments, whereby the vertical the eo f,.means to mount said die segments forhorizrontal rotatable movement,::theiun er ends of said, die segments 7 being free, to: swing into. and out of; alignment, horizontal means on each of said platemembers rotatable therewith, and: means onfsaid basesupport associatedly responsue to said carnmeans to laterally move said mountsin saidnguide means,' -vertical cam means onv each of said die 'support mounts and means oneach.- ofsaid die seg: mentsnassociatedly responsive to said vertical cam means to pivot said die segments vertically as the latte rotate horizontally, andpower drive means conjoined, to, said plate members rotatably movingrsaid die segments; and swinging .theinner endsv of said die segmentsiin arcuate paths 'into contiguous alignment to a predetermined final position so" as to stretch a'ndbend said metal strip fully about and upon said die forms, said power drive means being operable through said horizontal cam means to control the movement of said die support mounts.

2. The construction defined in claim 1, and in which said vertical cam means on each of said die support mounts is arranged at the outer side edge of said mount.

3. The construction defined in claim 1, and in which said means associatedly responsive to said horizontal cam means comprises a cam follower rotatably mounted in fixed position on said base support. r

V 4. In apparatus for stretch bending metal strips or hands, a base support, a pair of complementary, cam controlled, laterally movable, aligned die support mounts slidingly arranged on said base support, guide means for each of said sliding die support mounts, each of said mounts having a horizontally rotatable plate member swing of the die segments is toward and away from the a horizontal, means to mount said diesegments for horizontal rotatable movement, the inner ends of said die segments being free to swing into and out of alignment,

clamp means conjoined to the outer 'end of each die segment to releasably grip and hold said metal strip on'said die form adjacent the outer end thereof, horizontal cam means on each'of said plate members rotatable therewith and means on said base support associatedly responsive to said cam means to laterally move said mounts in said guide means, cam means on each of said die support mounts and means on each of said die segments associatedly responsive to said latter cam means to pivot said die segments in planes other than horizontal as said die segments rotate horizontally, and power drive means conjoined to said plate members rotatably moving said die segments and swinging the inner ends of said die segments in arcuate paths into contiguous alignment to a predetermined final position so as to stretch and bend said metal strip fully about and upon said die forms, said power drive means being operable through said horizontal cam means to control the movement of said die support mounts.

5. The construction defined in claim 4, and in which said cam means on each of said die support mounts is arranged vertically at the outer side edge of said mount.

6. The construction defined in claim 4, and in which said means associatedly responsive to said horizontal cam means comprises a cam follower rotatably mounted in fixed position on said base support.

7. In apparatus for stretch bending metal strips or hands, a base support, a pair of complementary, laterally movable, aligned die support mounts slidingly arranged on said base support, guide means for each of said sliding die support mounts, each of said mounts having a die segment with metal strip die form thereon rotatably supported and pivoted on said mount for swinging in a plane other than horizontal, means to mount said die segments for rotatable movement, the inner ends of said die segments being free to swing into and out of alignment, clamp means conjoined to the outer end of each die segment to releasably grip and hold said metal strip on said die form adjacent the outer end thereof, cam means on each of said means mounting said die segments for rotatable movement rotatable therewith and means on said base support associatedly responsive to said cam means to laterally move said mounts in said guide means, cam means on each of said die support mounts and means on each of said die segments associatedly responsive to said latter cam means to pivot each of said die segments in a plane other than horizontal as said-die segments rotate horizontally, and power drive means conjoined to said plate members rotatably moving said die segments and swinging the inner ends of said die segments in arcuate paths into contiguous alignment to a predetermined final position so as to stretch and bend 7 said metal strip fully about and upon said' die forms, said power drive means being operable through said hori-. zontal cam means to control the movement .of said die support mounts.

' 8'. The construction defined in claim 7, and in which said cam means on each of said die support mounts is arranged vertically at the outer side edge of said mount.

9 The construction defined in claim 7, and in which said means associatedly responsive to said first cam means comprises a cam follower rotatably mounted in fixed position on said base support.

10. In apparatus for stretch bending metal strips or hands, a base support, a pair of complementary, cam controlled, laterally movable, aligned die support mounts slidingly arranged on said base support, guide means for each of said sliding die support mounts, each of said mounts havinga horizontally rotatable plate member vertically pivoted on said mount and having'a die segment with metal strip die form thereon pivotally mounted on said plate member for swinging in a plane normal to the axis of the pivot, means to mount said die segments for horizontal rotatable movement, the inner ends of said die segments being free to swing into and out of alignment, clamp means conjoined to the outer end of each die segment to releasably grip and hold said metal strip on said die form adjacent the outer end thereof, horizontal cam means on each of said plate members rotatable therewith and means on said base support associatedly responsive to said cam means to laterally move said mounts in said guide means, cam means on each of said die support mounts and means on each of said die segments associatedly responsive to said latter cam means to pivot said die segments in planes normal to the axes of their pivots as said die segments rotate horizontally, and power drive means conjoined to said plate members rotatably moving said die segments and swinging the inner ends of said die segments in arcuate paths into contiguous alignment to a predetermined final position so as to stretch and bend said metal strip fully about and upon said die forms, said power drive means being operable through said horizontal cam means tto control the movement of said die support mounts.

References Citedin the tile of this patent UNITED STATES PATENTS 7 Lalli Sept. 22, 1959 

